|Analysis of the Characteristics of Inductively
Coupled Electrodeless Metal Halide Lamps
Kozo UEMURA and Toshihiko ISHIGAMI
Dimming of conventional metal halide lamps readily
causes changes in the lamp's color, decreases its efficacy,
and reduces its lifetime. Employing inductively coupled
electrodeless discharge in mercury-free metal halide
lamps led to less color change and greater efficacy
in dimming. The correlated color temperature of optimally
designed lamps, containing a dose of ScI3 - NaI - SnI2
and Xenon gas in the arc tube, was changed by only 300K
at the 30% dimming ratio. The general color rendering
index (Ra) did not shift greatly and the lamp's efficacy
could be kept at 89% of the rated wattage efficacy at
75% of the rated wattage (1/4 greater than the conventional
result). It was possible to correct the color characteristics
during dimming by adding new metal halides to the ScI3
- NaI - SnI2 lamp keeping improved dimming characteristics.
It was possible to correct color deviation and Ra by
adding suitable amounts of DyI3 or InI, though the lamp
efficacy decreased by about 10% at the rated wattage.
This has proved that the dimming performance of
metal halide lamps can be improved by employing inductively
coupled electrodeless discharge in optimally designed
mercury-free metal halide lamps.
KEYWORD: dimming, color, efficacy, electrodeless, DyI3, InI
Experimental Mass Culturing of Pavlova Lutheri Using
Step - Style Light Control
Hiroya OKUMURA, Kanji NAKAJIMA, Atsunori MASUDA, Mitsuo TAKAHASI,
Shinichi KOSAKA, Kimitoshi HORAGUCHI, Keiji MATSUYAMA and Katsusuke
The culturing of micro-algae is important to
the production of seeds for shellfish. We have developed
an economical method of doing this that uses step-style
light control to reduce the production cost, and appeared
light environment of the culture chamber. The light
intensity is increased 10% to 30% on the 3rd day (1.5
X 106cellsm -1), from 30% to 60% on the 6th day
(6.0?~106cellsm -1) and from 60% to 100% on the
9th day (1.4 X 107cellsm -1) of cultivation. We
cultivated P. lutheri using step-style light control
in a 200 - chamber; the other factors were same as for
conventional 100% stable light intensity cultivation.
The dark zone of the chamber, which was less initially
than 1Êmolm-2s-1, increased with the cell
density. It occupied 50% of the chamber at 1.5 X 107cellsm
-1 and 60% at 2.2 X 107cellsm -1. The growth curve
was identical to that for stable 100% light intensity.
Then it is possible that the consumption of electrical
power was 40% lower with step-style light control.
KEYWORD:microalgae, Pavlova lutheri, mass-culture, efficiently,
Illuminance Characteristics of Energy-saving Luminaire with
White-Light-Emitting Diode and a Solar-cell and BatterySystem
for Street Lighting
Tatsumi SETOMOTO, Yuji UCHIDA and Tsunemasa TAGUCHI
The illuminance characteristics of a next-generation
energy-saving luminaire for street lighting is described.
It consists of white-light-emitting diodes (LEDs) and
a solar-cell and battery system. A prototype luminaire
was constructed of two LED light sources, each of which
with a total of 700 units of 10-cd-class white LEDs.
The illuminance is normally 80 lx. When a person approaches
within 2m of the luminaire, a pyroelectric motion-sensor
senses the situation and the illuminance is increased
to about 660 lx. This is about 50 times brighter than
a white incandescent lamp. The luminous efficacy of
the white LED array source was estimated to be approximately
45lm/W at a forward-current of 1mA. Field testing showed
that this white LED lighting system did not suffer serious
deterioration in either it's brightness or electric
circuit over a period of one year.
KEYWORD:InGaN, white LED, energy-saving, solar cell, street lighting
Effect of Personal Control of Illumination on Satisfaction
of Office Lighting
Nuiko MIYASAWA, Yoshiki NAKAMURA and Naoki WAKASA
To clarify importance of personal adjustments
with office lighting, authors interviewed 17 general
office workers and 38 experts in lighting industry.
We also conducted the experiments to quantify the effect
that having the ability to change the illumination level
themselves had on the workers' satisfaction and to distinguish
between the effect resulting from "Control"
and one from the change itself.
The interviews showed that both the general office
workers and the lighting designers perceived lighting
adjustments as a key factor, while importance of the
adjustment was not recognized so much. The experiments
showed that evaluations of the luminous environment
differed greatly depending on whether the evaluator
was able to adjust the lighting level, while both the
effect resulting from "Control" and one from
the change in illumination level were slight.
KEYWORD:control, change in illumination level, office lighting,
satisfaction, interview, evaluation
The Operating Circuits with a Common By-pass Circuitfor
Multiple High-pressure Mercury Discharge Lamp -- Characteristics
of Circuit during Start-up and When a Lamp does not
Tadatsuna NONAKA and Michio IEMURA
Using both simulation and experiments, we investigated
cause to ensure that the supply current in an electrical
circuit with a common by-pass circuit can be kept approximately
constant from start-up to reaching steady state. In
such circuit, the supply current can be distorted by
about 2% when the power factor reaches 100%. We found
that an approximately constant supply current can be
achieved, thus making these circuits practical for use
with multiple high-pressure mercury discharge lamps,
even when a lamp does not light.
KEYWORD:multiple operating circuits, common by-pass circuit,